Telephone-transmitter.



UNITED STATES PATENT OFFICE.

a HENRY F. ALBRIGHT, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS."

TELEPHONE-TRANSMITTER.

Specification of Letters Patent.

Patented Sept. 4, 1906.-

To all 1072,0722, it may concern.-

Be it known that I, HENRY F. ALBRIGHT, a 'CIlJlZGIl of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Telephone- Transmitters, of which the following is a full, clear, concise, and exact description.

My invention relates to a telephone-transmitter of the type wherein granular carbon or other similar material is interposed-between a pair of electrodes adapted to be moved relatively to one another to vary the resistance between them.

My object is to provide a telephone of this type which will be simple and cheap to manufacture, efficient in operation, capable of easy and accurate adjustment, and when adjusted permanent and not easily deranged.

I will describe my invention by reference to the accompanying drawings, wherein Figure 1 is a view in cross-section of the several parts of a transmitter embodying my invention, showing said parts in the relative positions in which they are assembled. Fig. 2 is a rear view of the device with the back of the case removed. Fig. 3 is a front view with the front of the case and the mouth piece removed. Fig. 4 is a longitudinal sectional view of the transmitter, and Fig. 5 is a detail View of a portion of the device.

The same reference-letters are used to designate the same parts wherever shown.

The front plate a, which is a substantial brass casting adapted to support the operating parts of the transmitter, is provided with a central opening a, having a bridge-piece a extending across the same and adapted to form a rigid support for a carbon electrode immediately behind said opening. Preferably, the bridgepiece comprises a ring a with threads on its periphery screwing into the threaded central opening a and having the cross bar or bridge proper formed inte grally with said ring and extending diametrically across the same to support the elec trode. The ring a may be slit, so that it will have a tendency to spread, and thus have a spring engagement with the threaded opening of the supporting-plate The bridgepiece may thus be permanently adjusted backward or forward to any desired position within the opening a.

The carbon electrode 1) is fastened to a block b, which is supported on the bridgepiece (1 Said block b has passes through a bore in the bridge a and a nut b is screwed upon the threaded. end of the shank b to hold the block and electrode firmly in. place, a lock-nut 5'' being preferably added to hold the nut 1) against turning.

The main diaphragm c carries upon its periphery the usual damping-ring c and is adapted to be yieldingly pressed against the inner face of the supporting-pl ate (i by means of springs d (1, having pads of rubber, felt, or other suitable material upon their ends.

A cup or chamber a is secured to the rear side of the diaphragm c by any suitable means-such as rivets passing through the diaphragm and the angularly-projecting rim of the chamber-the diaphragm 0 having an opening 0 therein, through which the elec trode b enters the chamber. An electrode 7, preferably of carbon, is secured within the cup 6 to partake of the movement of the diaphragm and is preferably mounted upon a supporting-plate 7, having a shankf passing through a hole in the rear wall of the chamber, a nut f being adapted to screw upon the threaded end of the shank, and thus secure the electrode in place. The shank f a shank N, which may also serve as the point of attachment for a conductor Z, which electrically connects the electrode f by way of the plate f and shank f with a binding-post g, which is mounted upon but insulated from the plate a. The side walls of the chamber 6 may be provided with an inner lining of paper or other suitable material to insulate the same from the granules within the chamber.

I preferably provide an annular supple mentary diaphragm h, adapted to cooperate with the supporting-block b of the electrode 1) to close the opening in the main diaphragm 0, leading into the chamber 6.

he supporting-block b is provided with a binding-nut 6 adapted to screw thereon to clamp the inner edge of the annular supplementary diaphragm against the block. The outer edge of the supplementary diaphragm is clamped between said main diaphragm and the rim of the cup 6. The supplemen tary diaphragm should be of flexible ma terlal, and I prefer to use a thinmica washer for this purpose. A perfect sealed chamber therefrom,

is thus provided for the granules 'L of carbon or other suitable conducting material, which are placed therein between the opposing electrodes 1) The transmitter may also have an outer inclosing case formed of two cup-shaped parts 10 7c, the front part. or cap 10 being adapted to fit over the part it. Each of the said parts k is has a number of L-shaped slots Z Ztherein, adapted to receive pins 1 Z which project from the supporting-plate a of the transmitter. The trnasmitter is first placed within the rear part or base 7c of the case and the pins Z caused to enter the slots Z of said part to form a bayonet-joint engagement. he front part or cap is then fitted over the part 1: and the pins Z caused to enter the slots Z in the said cap, thus forming a second bayonet-joint. WVith this arrangement the parts of the inclosing case and the transmitter may be easily, quickly, and securely locked together. The cap is has an opening k therein, through which a suitable mouthpiece m may pass, said mouthpiece being screwed into the plate a over the opening a therein.

In the transmitter above described when sound-waves impinge upon the main diaphragm c said diaphragm is set in vibration, causing the electrode f, secured thereto, to approach the stationary electrode 1), carried by the front supporting-plate a and to recede and so to vary the electrical resistance of the granules between said elec trodes.

By virtue of my invention, as above described, I am enabled to produce a transmitter whose parts are compactly arranged and which will possess great rigidity of construction, durability, and efficiency in operation, while being cheap to manufacture and easy to assemble and adjust. To adjust the transmitter, it is simply necessary to turn the bridge-piece a to vary the position of the stationary electrode 15. The provision of this adjustable bridge-piece a makes it possible to obtain great accuracy and delicacy of adjustment of the transmitter. The diaphragm will be in its natural position at the time of adjustment, and the bridge-piece when moved is held firmly and securely in its adjusted position, so that any adjustment made is absolutely permanent.

I claim 1. In a telephonetransmitter, the combination with a front supp orting-plate having .a central opening therein, of a bridge-piece mounted in said opening, an electrode carried by said bridge-piece immediately behind said opening, a diaphragm pressed at its outer edge against said plate, a cup carried upon the rear side of saiddiaphragm, said diaphragm having an opening at the mouth which said electrode of said cup through passes into the cup, an electrode secured diaphragm pressed at pressed at within said cup, and granules of conducting material in said cup between said electrodes.

2. In a telephone-transmitter, the combination with a supporting-plate having a central opening therein, of a bridge-piece mounted in said opening, an electrode, a supporting-block therefor carried by said bridgepiece immediately behind said opening, a

its outer. edge against said plate, a cup upon the rear side of said diaphragm and having an angularly-projecting rim secured thereto, said diaphragm having an opening therein at the mouth of the cup through which said electrode passes into the cup, an electrode secured within said cup, and granules of conducting material within said cup between said electrodes.

3. In a telephone-transmitter, the combination with a front supporting-plate having a central-opening therein, of a bridge-piece mounted in said opening, an electrode, a supporting-block therefor carried by said bridge immediately behind said opening, a diaphragm pressed at its outer edge against said plate, a cup upon the rear side of said diaphragm and having an angularly-projecting rim secured thereto, said diaphragm having an opening therein at the mouth of the cup through which said electrode passes into the cup, an electrode secured within the cup, a binding-nut for said supporting-block, a supplementary diaphragm secured at its outer edge to said main diaphragm and at its inner edge between said supporting-block and its binding-nut, and granules of conducting ma terial in said cup between said electrodes.

4. In a telephone-transmitter, the combination with a front supporting-plate having a central opening therein, of a diaphragm pressed at its outer edge against said plate, a cup carried by said diaphragm, said diaphragm having an opening at the mouth of said cup, an electrode secured within said cup, a bridge-piece adjustably mounted in theopening in the supporting-plate, an electrode carried by said bridge and facing the mouth of said cup, and granules of conducting material in said cup between said elec trodes.

5. In a telephone-transmitter the combination with a front supporting-plate having a central opening therein, of a diaphragm its outer edge against said plate, a cup carried by said diaphragm, said diaphragm having an opening at the mouth of the cup, an electrode secured within said cup, a ring adjustably mounted within the opening in the supporting-plate, a bridge of said opening carried by said ring, an electrode carried by said bridge-piece and passing into said cup through the mouth thereof, and granules of conducting material in said cup between said electrodes.

6. In a telephone-transmitter, the combination with a front supporting-plate having a central opening therein, of a diaphragm pressed at its outer edge against said plate, a cup carried by said diaphragm, said diaphragm having an opening at the mouth of said cup, an electrode secured within said cup, a ring adapted to screw into the sides of the opening in the supporting-plate, a bridge of said opening carried by said ring, an electrode carried by said bridge and passing into said cup through the mouth thereof, the periphery of said ring being slit, whereby said ring tends to spread and may be permanently adjusted to any position within said opening, and granules of conducting material within said cup between said electrodes.

7. In a telephone-transmitter, the combination with a front supporting-plate having an opening therein, of a diaphragm pressed at its outer edge against said plate, a cup having an angularly-projecting rim secured to said diaphragm, said diaphragm having an opening at the mouth of said cup, an electrode secured within the cup, a. ring adjustably mounted within the opening in said supporting-plate, a bridge of said opening carried by said ring, a second electrode projecting into said cup, a supporting-block therefor carried by said bridge-piece, a supplementary diaphragm secured at its outer edge between the rim of said cup and main diaphragm, and at its inner edge to said supporting-block, and carbon granules within said cup between said electrodes.

8. The combination with a telephonetransmitter having a supporting-plate a provided with a central opening therein, of a cup-shaped base adapted to receive said transmitter, Lshaped slots in said base, pins carried by said supporting-plate adapted to enter said slots to form a bayonet-joint engagement, a cap adapted to fit over said base and having a central opening therein, L-

shaped slots in said cap adapted to receive said pins to form a second bayonet-joint engagement, and a mouthpiece m passing through the opening in said cap and secured to the supporting-plate over the opening therein.

9. In a telephone-transmitter, the combination with a front supporting-plate having a central opening therein, of a diaphragm mounted at the rear of said plate, an electrode moving with the diaphragm, a second electrode in operative relation to said firstmentioned electrode, and an adjustable bridgepiece in said opening adapted to control the adjustment between said electrodes.

10. In a telephone-transmitter, the combination with a front supporting-plate having a central opening therein, of a diaphragm mounted at the rear of said plate, an electrode carried by said diaphragm, a bridgepiece adjustably mounted in the opening in the supportingplate, and an electrode carried by said bridge-piece in operative relation to said first-mentioned electrode.

11. In a telephone-transmitter, the combination with a front supporting-plate having a central opening therein, of a diaphragm mounted at the rear of said plate, a cup carried upon the rear of said diaphragm, said diaphragm having an opening at the mouth of said cup, an electrode secured within said cup, a second electrode movably mounted immediately behind the opening in said supporting-plate and facing the mouth of said cup, and granules of conducting materials in said cup between said electrodes.

In witness whereof I hereunto subscribe my name this 6th day of July, A. D. 1904.

HENRY F. ALBRI GHT.

I/Vitnesses:

W. J. BAUOKER, JAS. E. HAYES, Jr. 

